package com.kobe.game_40;

/**
 * 
 * Let d(n) be defined as the sum of proper divisors of n (numbers less than n
 * which divide evenly into n). If d(a) = b and d(b) = a, where a b, then a and
 * b are an amicable pair and each of a and b are called amicable numbers.
 * 
 * For example, the proper divisors of 220 are 1, 2, 4, 5, 10, 11, 20, 22, 44,
 * 55 and 110; therefore d(220) = 284. The proper divisors of 284 are 1, 2, 4,
 * 71 and 142; so d(284) = 220.
 * 
 * Evaluate the sum of all the amicable numbers under 10000.
 * 
 * 
 */
public class Game21 {

    public static void main(String[] args) {

        int result = 0;
        for (int i = 1; i < 10000; i++) {
            if (i == getD(getD(i)) && i != getD(i)) {
                result += i;
            }
        }
        System.out.println(result);
    }

    private static int getD(int number) {
        int sum = 0;
        for (int i = 1; i < number; i++) {
            if (number % i == 0) {
                sum += i;
            }
        }
        return sum;
    }
}
